Jonathan is the chief executive of NICE. Jonathan joined NICE in January 2023 as chief medical officer and in March 2023 became interim director of the centre for guidelines. Jonathan was subsequently appointed deputy chief executive in May 2024 and chief executive in December 2025.

Prior to this he was the interim chief clinical information officer (CCIO) at NHS England (2022), the chief medical officer (CMO) of NHS Digital (2019 to 2022), and the national clinical director for urgent and emergency care at NHS England (2013 to 2019).

In his clinical work, Jonathan is a consultant in emergency medicine at the Bristol Royal Infirmary and also does regular shifts with the Great Western Air Ambulance, which he established as its first medical advisor between 2007 and 2011.

Jonathan is professor of emergency care in the school of health and social wellbeing at the University of the West of England, and a National Institute for Health Research (NIHR) senior investigator. His main research interests relate to cardiac arrest, emergency and pre-hospital care, service organization and delivery, and design research.